The invention relates to a thermal ink jet composition, a printing process and a method of improving the fast dry characteristics of inks.
Ink jet printing systems generally are of two types: continuous stream and drop-on-demand. In continuous stream ink jet systems, ink is emitted in a continuous stream under pressure through at least one orifice or nozzle. The stream is perturbed, causing it to break up into droplets at a fixed distance from the orifice. At the break-up point, the droplets are charged in accordance with digital data signals and passed through an electrostatic field that adjusts the trajectory of each droplet in order to direct it to a gutter for recirculation or to a specific location on a recording medium. In drop-on-demand systems, a droplet is expelled from an orifice directly to a position on a recording medium in accordance with digital data signals. A droplet is not formed or expelled unless it is to be placed on the recording medium.
Quality thermal ink jet printing can be achieved by utilizing an aqueous ink composition containing at least one dye or pigment, a wetting agent and water. U.S. Pat. No. 4,508,570 to Fujii et al. discloses an aqueous ink for ink jet printing, which comprises a water-soluble direct dye and/or acid dye, a polyhydric alcohol and/or an alkyl ether thereof, water, and at least one water-soluble non-ionic surface active agent selected from a specified polyoxyethylene alkyl amine, a specified polyoxyethylene alkyl phenyl ether and a specified polyoxyethylene alkyl ether.
U.S. Pat. No. 4,026,713 to Sambucetti et al. relates to a magnetic ink containing non-ionic, cationic and/or anionic surfactants. The surfactants may include glycerol, a lower alkyl monoether of ethylene glycol and/or a polyethylene diol.
U.S. Pat. No. 4,914,562 to Abe et al. discloses an ink jet composition containing an ionic surface active agent or a non-ionic surface active agent. The ionic surface active agent can be a dioctyl sulfosuccinate sodium salt, sodium oleate or dodecylbenzenesulfonic acid. The non-ionic surface active agent may be diethylene glycol mono-n-butyl ether or triethylene glycol mono-n-butyl ether.
U.S. Pat. No. 5,019,166 to Schwarz relates to a thermal ink jet printing composition comprising a dye, a liquid medium and a surfactant selected from the group consisting of polyoxyalkylated ethers, anionic bitail fluorothio alkyls, alkyl aryl sulfonates, alkyl amine quaternary salts and mixtures thereof.
U.S. Pat. No. 5,116,409 to Moffatt discloses a process for reducing color bleed of inks employed in thermal ink jet printing. The process comprises printing two inks side by side, each ink having a composition comprising (a) a vehicle and (b) about 0.1 to 10 wt. % of at least one water-soluble anionic dye. The vehicle comprises at least one member selected from the group consisting of zwitterionic surfactants and non-ionic amphiphiles and water or water and an organic solvent. Moffatt discloses a composition that includes SURFYNOL S465, an acetylenic polyethylene oxide, and 1,5-pentanediol.
U.S. Pat. No. 5,254,159 to Gundlach et al., the entire disclosure of which is herein incorporated by reference, discloses an ink composition that comprises water, an anionic dye and an amine compound. The ink composition provides waterfast images. U.S. Pat. No. 5,540,765 to Gundlach et al., the entire disclosure of which is incorporated herein by reference, discloses an ink jet printing composition containing a surfactant comprising an alkylsulfoxide and preferably containing a betaine zwitterionic base and dibutylsulfoxide. U.S. Pat. No. 5,531,815 to Gundlach et al., the entire disclosure of which is herein incorporated by reference, discloses a thermal ink jet printing composition that contains a betaine zwitterionic base and a quasisurfactant penetrant.
Japanese Patent Abstract 88-165465, the entire disclosure of which is incorporated herein by reference, discloses a quick-drying ink jet ink composition containing sodium dodecylbenzenesulfonate and a mixture of a polyhydric alcohol (e.g., glycerol) and a polyhydric alcohol derivative (e.g., diethylene glycol monobutyl ether).
Full color printing in a thermal ink jet printing process requires an ink with fast dry characteristics. Fast dry characteristics can be improved by the addition of a penetrant. A penetrant imparts quick-dry characteristics to a thermal ink jet ink composition.
However, effectiveness of a penetrant in providing quick-dry characteristics varies with ink composition solvent. Some penetrants do not provide acceptable quick-dry characteristics to some ink-solvent systems. Co-solvents can be added to ink compositions to improve effectiveness of the penetrant, or the penetrant concentration in the ink compositions can be increased to achieve satisfactory quick-dry characteristics. However, some co-solvent packages and/or higher penetrant concentrations cause deterioration of thermal ink jet hardware. For example, higher loads (i.e., weight percentage) of butylcarbitol or higher loads of cyclohexyl pyrrolidinone aggressively attack cartridge materials and seals. Effectiveness of penetrants in providing quick-dry characteristics varies with ink solvents. Many surfactants such as Merpols and Surfynols are chemically aggressive towards thermal ink jet printhead materials. Utilization of the standard quasisurfactant penetrants such as butylcarbitol and cyclohexylpyrrolidinone also compromise the integrity of thermal ink jet printhead materials when used in otherwise appropriate loadings.
Thus, there continues to be a need for ink jet ink compositions having fast dry characteristics and that do not cause deterioration of ink jet ink hardware.